#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

int main() {
	
	string s1,s2;
	cin>>s1>>s2;
	int n=static_cast<int>(s1.size());
	int m=static_cast<int>(s2.size());
	vector<vector<int>> dp(n+1,vector<int>(m+1));
	for(int i=1;i<=n;++i){
		dp[i][0]=i;
	}
	for(int j=1;j<=m;++j){
		dp[0][j]=j;
	}
	for(int i=1;i<=n;++i){
		for(int j=1;j<=m;j++){
			if(s1[i-1]==s2[j-1]){
				dp[i][j]=dp[i-1][j-1];
			}
			else{
				dp[i][j]=min(dp[i-1][j],min(dp[i-1][j-1],dp[i][j-1]))+1;
			}
		}
	}
	cout<<dp[n][m];
	
	return 0;
}
